Pharmacology and Drug Interactions
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Questions and Answers

What is the primary mechanism of action of aspirin in relation to platelet aggregation?

  • Inhibition of platelet activation
  • Reversible inhibition of thromboxane A2 synthesis
  • Stimulation of thromboxane A2 synthesis
  • Irreversible inhibition of thromboxane A2 synthesis (correct)

    • What is the effect of aspirin on gastric mucosa?

  • It protects the gastric mucosa from irritation
  • It stimulates the production of gastric mucus
  • It irritates the gastric mucosa, causing epigastric distress (correct)
  • It has no effect on the gastric mucosa

    • What is the effect of long-term intake of large doses of aspirin on clotting factors?

  • It stimulates the production of vitamin K
  • It has no effect on clotting factors
  • It decreases the synthesis of clotting factors in the liver (correct)
  • It increases the synthesis of clotting factors in the liver

    • What is the duration of aspirin's effect on platelet aggregation?

    <p>About a week</p> Signup and view all the answers

    What is the therapeutic effect of aspirin in analgesic doses?

    <p>Only analgesic and antipyretic effects</p> Signup and view all the answers

    What is the effect of aspirin on bleeding time?

    <p>It increases bleeding time</p> Signup and view all the answers

    What is the pharmacological action of salicylic acid released from aspirin?

    <p>Analgesic, antipyretic, and anti-inflammatory actions</p> Signup and view all the answers

    What is the effect of prophylactic vitamin K therapy on bleeding risk associated with long-term aspirin intake?

    <p>It decreases the bleeding risk</p> Signup and view all the answers

    What is the limiting factor in the absorption of aspirin?

    <p>Poor water solubility</p> Signup and view all the answers

    What is the plasma half-life of aspirin, considering its conversion to salicylic acid?

    <p>3-5 hours</p> Signup and view all the answers

    What is a rare but serious adverse effect of aspirin in children with viral infections?

    <p>Reye's syndrome</p> Signup and view all the answers

    What is the result of salt and water retention caused by aspirin?

    <p>Electrolyte imbalance</p> Signup and view all the answers

    Which of the following is a therapeutic effect of NSAIDs?

    <p>Analgesia</p> Signup and view all the answers

    What is the characteristic of hypersensitivity reactions to aspirin?

    <p>Idiosyncratic and infrequent</p> Signup and view all the answers

    What is the syndrome caused by anti-inflammatory doses of aspirin?

    <p>Salicylism</p> Signup and view all the answers

    Which of the following is a characteristic of COX-2 inhibitors?

    <p>Less gastric mucosal damage</p> Signup and view all the answers

    What is the most common age group affected by acute salicylate poisoning?

    <p>Children</p> Signup and view all the answers

    What is a possible adverse effect of NSAIDs on the CNS?

    <p>Seizure precipitation</p> Signup and view all the answers

    What is the outcome of long-term therapy with high-dose aspirin?

    <p>Insidious onset hepatic injury</p> Signup and view all the answers

    What is the primary mechanism of action of nonsteroidal anti-inflammatory drugs?

    <p>Inhibition of COX-1 and COX-2 enzymes</p> Signup and view all the answers

    Which of the following is a possible interaction of NSAIDs with other drugs?

    <p>Decreased antihypertensive effect with β blockers</p> Signup and view all the answers

    Which of the following is NOT a therapeutic effect of analgesics?

    <p>Cure of the underlying disease causing pain</p> Signup and view all the answers

    What is a possible adverse effect of NSAIDs on the renal system?

    <p>All of the above</p> Signup and view all the answers

    What is the primary difference between opioid and non-opioid analgesics?

    <p>Mode of action in the CNS</p> Signup and view all the answers

    Which of the following is a characteristic of nonselective COX inhibitors?

    <p>They inhibit platelet function</p> Signup and view all the answers

    Which of the following NSAIDs is a preferential COX-2 inhibitor?

    <p>Celecoxib</p> Signup and view all the answers

    What is a possible adverse effect of NSAIDs on the gastrointestinal system?

    <p>All of the above</p> Signup and view all the answers

    Which of the following is a therapeutic effect of NSAIDs?

    <p>Antiinflammatory</p> Signup and view all the answers

    What is the mechanism of action of paracetamol?

    <p>Unknown, but thought to involve the CNS</p> Signup and view all the answers

    Which of the following is a common adverse effect of NSAIDs?

    <p>Gastrointestinal bleeding</p> Signup and view all the answers

    What is the role of slow-reacting substance of anaphylaxis (SRS-A) in the body?

    <p>Mediation of anaphylactic and allergic reactions</p> Signup and view all the answers

    Which of the following is an example of a propionic acid derivative NSAID?

    <p>Naproxen</p> Signup and view all the answers

    What is the role of leukotriene B4 in asthma?

    <p>It enhances chemotactic and chemokinetic responses in human neutrophils, monocytes, and eosinophils</p> Signup and view all the answers

    What is the effect of COX-1 and COX-2 inhibitors on lipoxygenases?

    <p>They inhibit lipoxygenases</p> Signup and view all the answers

    What is the therapeutic effect of prostacyclin (PGI2)?

    <p>Vasodilation and inhibition of platelet aggregation</p> Signup and view all the answers

    What is the function of lipoxin A4 (LXA4)?

    <p>Vasodilation and inhibition of neutrophil adhesion and chemotaxis</p> Signup and view all the answers

    What is the mechanism of action of aspirin?

    <p>Inhibition of COX-1 and COX-2</p> Signup and view all the answers

    What is the therapeutic effect of prostaglandin E2 (PGE2)?

    <p>Analgesia and anti-inflammation</p> Signup and view all the answers

    What is the effect of leukotriene C4 (LTC4) on the bronchi?

    <p>Constriction of the bronchi</p> Signup and view all the answers

    What is the effect of thromboxane A2 (TXA2)?

    <p>Vasoconstriction and promotion of platelet aggregation</p> Signup and view all the answers

    What is the maximum dose of ketorolac that can be administered in a day?

    <p>90 mg</p> Signup and view all the answers

    What is the percentage of nimesulide bound to plasma proteins?

    <p>99%</p> Signup and view all the answers

    What is the primary use of nimesulide?

    <p>Short-term management of moderate pain</p> Signup and view all the answers

    What is a characteristic of nimesulide compared to other NSAIDs?

    <p>It is a weak inhibitor of PG synthesis and moderately COX-2 selective</p> Signup and view all the answers

    What is a common adverse effect of ketorolac?

    <p>All of the above</p> Signup and view all the answers

    What is the advantage of selective COX-2 inhibitors compared to traditional NSAIDs?

    <p>They cause less gastric mucosal damage</p> Signup and view all the answers

    What is the effect of selective COX-2 inhibitors on PGI2 production?

    <p>It is decreased</p> Signup and view all the answers

    What is the primary action of paracetamol?

    <p>Analgesic and antipyretic</p> Signup and view all the answers

    Why should selective COX-2 inhibitors be used with caution?

    <p>Due to their risk of cardiovascular events</p> Signup and view all the answers

    What is the effect of paracetamol on platelet aggregation?

    <p>It has no effect on platelet aggregation</p> Signup and view all the answers

    What is the plasma half-life of diclofenac?

    <p>2 hours</p> Signup and view all the answers

    What is a common adverse effect of diclofenac?

    <p>Headache</p> Signup and view all the answers

    What is the primary use of diclofenac?

    <p>Short-lasting painful inflammatory conditions</p> Signup and view all the answers

    What is the mechanism of action of diclofenac in terms of COX inhibition?

    <p>Somewhat COX-2 selective</p> Signup and view all the answers

    What is the dose of diclofenac for short-lasting painful inflammatory conditions?

    <p>100 mg BD</p> Signup and view all the answers

    What is the percentage of ketorolac excreted unchanged in urine?

    <p>60%</p> Signup and view all the answers

    Which of the following is a common adverse effect of piroxicam?

    <p>Heartburn</p> Signup and view all the answers

    What is not a known use of piroxicam?

    <p>Hypertension</p> Signup and view all the answers

    What is the mechanism of action of ketorolac in relieving pain?

    <p>Peripherally acting by inhibiting PG synthesis</p> Signup and view all the answers

    What is the plasma half-life of piroxicam?

    <p>2 days</p> Signup and view all the answers

    Mephenamic acid exerts its analgesic action in which parts of the body?

    <p>Both peripheral and central nervous systems</p> Signup and view all the answers

    What is a rare but serious complication of Mephenamic acid?

    <p>Haemolytic anaemia</p> Signup and view all the answers

    What is Piroxicam known for?

    <p>All of the above</p> Signup and view all the answers

    In which type of pain, is Mephenamic acid primarily indicated?

    <p>Muscle and joint pain</p> Signup and view all the answers

    What is the dosing frequency of Mephenamic acid?

    <p>250-500 mg TDS</p> Signup and view all the answers

    What is the primary route of elimination of propionic acid derivatives, including ibuprofen?

    <p>Both urine and bile</p> Signup and view all the answers

    Which of the following is a contraindication for prescribing ibuprofen?

    <p>Pregnancy</p> Signup and view all the answers

    What is the primary use of ibuprofen?

    <p>Both b and c</p> Signup and view all the answers

    What is a common CNS side effect of ibuprofen?

    <p>All of the above</p> Signup and view all the answers

    How much is the usual dose of ibuprofen?

    <p>400-600 mg</p> Signup and view all the answers

    What percentage of paracetamol is protein-bound in plasma?

    <p>about 1/4</p> Signup and view all the answers

    What is the plasma half-life of paracetamol?

    <p>2–3 hours</p> Signup and view all the answers

    What is a common adverse effect of paracetamol?

    <p>nausea and rashes</p> Signup and view all the answers

    In which age group can paracetamol be used?

    <p>infants to elderly</p> Signup and view all the answers

    What is the dose of paracetamol for children?

    <p>10–15 mg/kg</p> Signup and view all the answers

    Why is paracetamol preferred over NSAIDs in certain cases?

    <p>it does not prolong bleeding time</p> Signup and view all the answers

    What is a use of paracetamol?

    <p>as an antipyretic</p> Signup and view all the answers

    How often should paracetamol be taken?

    <p>3–4 times a day</p> Signup and view all the answers

    What is the duration of action of paracetamol?

    <p>3–5 hours</p> Signup and view all the answers

    Why is paracetamol used in pregnant or lactating women?

    <p>because it is safer than NSAIDs</p> Signup and view all the answers

    Study Notes

    Nonsteroidal Anti-Inflammatory Drugs (NSAIDs)

    • Definition: NSAIDs are a group of drugs that relieve pain, reduce inflammation, and lower fever.
    • Classification:
      • Nonselective COX inhibitors
      • COX-2 inhibitors (e.g. celecoxib, etoricoxib)
      • Preferential COX-2 inhibitors (e.g. nimesulide)
      • Analgesic-antipyretics with poor anti-inflammatory action (e.g. paracetamol)

    Mechanism of Action

    • Inhibit cyclooxygenase (COX) enzymes, which convert arachidonic acid to prostaglandins and thromboxane
    • Reduce prostaglandin production, leading to decreased pain and inflammation
    • COX-1 is responsible for platelet aggregation and gastric mucosal protection, while COX-2 is involved in inflammation

    Pharmacological Actions of Aspirin

    • Analgesic, antipyretic, and anti-inflammatory effects
    • Irreversibly inhibits thromboxane A2 synthesis, leading to prolonged bleeding time
    • Decreases synthesis of clotting factors in liver, increasing risk of bleeding
    • High doses can cause salt and water retention, vertigo, and tinnitus

    Adverse Effects of Aspirin

    • Hypersensitivity and idiosyncrasy
    • Anti-inflammatory doses can cause salicylism, leading to dizziness, tinnitus, and electrolyte imbalance
    • Long-term therapy can cause hepatic injury and Reye's syndrome in children
    • Acute salicylate poisoning can cause coma and death

    Features of NSAIDs

    • Nonselective COX inhibitors:
      • Analgesic, antipyretic, and anti-inflammatory effects
      • Increase risk of gastrointestinal bleeding and ulceration
      • May cause renal salt and water retention, and delay or prolong labor
    • COX-2 inhibitors:
      • Analgesic, antipyretic, and anti-inflammatory effects
      • Less gastrointestinal toxicity
      • May increase risk of cardiovascular events

    Examples of NSAIDs

    • Salicylates (e.g. aspirin)
    • Propionic acid derivatives (e.g. ibuprofen, naproxen, ketoprofen)
    • Enolic acid derivatives (e.g. piroxicam)
    • Acetic acid derivatives (e.g. ketorolac)
    • Fenamates (e.g. mephenamic acid)
    • COX-2 inhibitors (e.g. celecoxib, etoricoxib)

    Pharmacokinetics and Interactions

    • NSAIDs are well absorbed orally, metabolized in the liver, and excreted in the urine
    • May interact with other medications, such as diuretics, anticoagulants, and antihypertensives
    • May cause displacement interactions due to high protein binding

    Contraindications and Precautions

    • NSAIDs are contraindicated in patients with active peptic ulcer, bleeding disorders, and hypersensitivity
    • Use with caution in patients with cardiovascular disease, hypertension, and kidney disease
    • Avoid use in pregnant women, especially in the third trimester

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    Description

    This quiz covers the interactions between different medications, including oral anticoagulants, sulfonylureas, and more. Learn about the risks and effects of combining these drugs.

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